The present invention relates to apparatus for forming wire fabric cages used in reinforcing concrete pipe. In the manufacture of pipe reinforcing cages, wire fabric is typically passed through a set of forming rollers which bend it into a cylinder. Its ends are then welded together. Such a system is represented by U.S. Pat. No. 3,678,971 issued July 25, 1972 to Alfred A. Nordgren. Also, cages have been manufactured by laying out the longitudinal wires for the pipe cage and holding them in position while circumscribing them with a spiral wrap wire, welding the junctions to complete the cage. Such a system is disclosed in U.S. Pat. No. 3,437,114 issued Apr. 8, 1969 to D. P. Whitacre et al.
Both of the above methods are time-consuming. After cages are formed by bending them through forming rollers, the ends of the fabric must be welded. Such welding is typically done manually and automatic welders for such cages have not been particularly commercially successful.
Both the Nordgren and Whitacre machines require readjustment every time one wants to manufacture different sized cages. Thus, the machine must first be set up for a run of a large number of cages. To then do cages of a different size, the machine has to be reset up for the new sized cages.
This is inconvenient since cage assemblies are frequently used in which a smaller diameter cage is positioned inside a larger diameter cage for subsequent molding into a concrete pipe. The necessity of doing large runs requires that a number of cages of the same size be stored at some point on the manufacturing floor for later assembly with different sized cages of a subsequent run.